Doorknob fastener



Aug. 25, 1942. w, SCHLAGE noommos FASTENER Filed March 12, 1941 PatentedAug. 25, 1942 U N i 'i E SAT S 'i'T FHCE DOGRKNOB FASTENER ApplicationMarch 12, 1941, Serial No. 382,875"? 3 Claims.

This invention relates to a doorknob fastener,

and especially to a fastener which is intended for the exterior knob ofa door.

There are a number of different types of fastening means whereby adoorknob may be secured to a spindle, but practically all of these,whether they be setscrews, yieldable detents, latches or the like, areaccessible from the exterior of the lock, and if the fastener on theexterior or outer knob is removable, entrance might be gained.

The object of the present invention is to provide a fastener which isapplicable particularly to the outer knob, to provide a fastener for theouter knob which is applied from the inner end of the spindle, toprovide a fastener in the form of a latch which projects wholly throughthe spindle into a keeper in the knob, and further, to provide meansinsertable from the inner end of the spindle for dogging and retainingthe radially movable latch from disengagement with the keeper.

The knob fastener is shown by way of illustration in the accompanyingdrawing, in which Fig. 1 is a longitudinal Vertical section of one endof a hollow spindle, showing a knob applied thereto and the insertablefastener unit whereby the knob is secured against removal;

Fig. 2 is a perspective view of a hollow spindle, said view beingpartially broken away;

Fig. 3 is a cross section taken on line IfI-III of Fig. 1;

Fig. 4 is a perspective view of the type of latch or fastener shown inFig. 3;

Fig. 5 is a perspective view of the latch retainer;

Fig. 6 is a section similar to Fig. 1, showing a modified form of latchretainer; and

Fig. 7 is a perspective view of a'doorknob.

Referring to the drawing in detail, and particularly to Figs. 1, 4 and'7, A indicates a tubular spindle in the outer end of which are formedtwo cross-slots 2 and 3. Adapted to be applied to the outer and of thespindle is a knob 4 having a shank 5, and formed in the shank is akeeper or cross slot 6 which is adapted to register with the spindleslot 2 when the knob is in place.

Mounted within the spindle is a fastener in the form of a plate whichhas a central opening 1 formed therein, and at one end a latch 8 and onthe opposite end a pair of spaced lugs 99. These lugs are guided in thecross-slot 2 of the spindle, while the latch 8 is guided in the slot 3;further, it is of sufficient length to project through said slot andinto the keeper or cross-slot 6 formed in the shank of the knob, asclearly shown in Figs. 1 and 2.

The outer end of the latch 8 is exposed, and unless means are providedfor positively retaining the latch when projected into the keeper, itcould be depressed and the outer knob removed, with the result that animplement could be inserted through the outer end of the hollow spindleto actuate the lock mechanism and open the door. Such manipulation,particularly by an unauthorized person, would be anything but desirable,and the main purpose of the invention is accordingly to provide afastener for the outer knob of a door which cannot be depressed,released or otherwise tampered with.

The means employed in the present invention to render the latchnon-depressible and otherwise tamper-proof is exceedingly simple. Itconsists of a sleeve l0 (see. Fig. 5) which is slotted longitudinally asindicated at I i to render it circumferentially contractable andexpandable. By applying finger pressure to opposite sides of the sleeveit is contracted sufiiciently to permit it to be readily inserted in theinner end of the spindle, and when it is inserted it reexpands andfrictionally engages the inner surface of the spindle. It is then pushedby a suitable implement through the spindle towards the latching plate,and as it moves into engagement therewith a pair of dogs [2 formed onthe forward end of the sleeve will enter between the lugs 99 of thelatching plate, or in other words will become interposed between theinner wall of the spindle and the latching plate, and thereby dog orretain the latch in projected position and against depression from theexterior.

Another form of the dogging member is shown in Fig. 6. In this instancethe sleeve carries a pin M which extends through the central opening inthe latching plate, thereby retaining it in extended position andagainst depression.

The whole fastener or latching mechanism consists of only two parts,to-wit, the latching plate and the sleeve which carries the dog or dogs.These parts are made from sheet metal by punch and die formingoperations, and thus are cheap to manufacture; and as they are alsoreadily installed or placed in the spindle, labor cost is also low. Bethat as it may, a fastener is provided which is particularly adaptableto the outer knobs of door looks, as the fastener cannot be removed fromthe exterior; it can only be released from the inner end of the spindle,

and then only by pulling the sleeve and dog inwardly and away fromengagement with the latch plate.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

1. In a structure of the character described, a tubular spindle having aslot formed therein, a knob having a keeper adapted to register with theslot when the knob is applied tothe spindle, a radially movable latchmounted in the spindle, a dogging member insertible in the spindle andengageable with the latch to project it through the slot in the spindleand into the keeper in the knob, and friction held means for retainingthe dogging member in engagement with the latch.

2. In a structure of the character described, a tubular spindle having aslot formed therein, a knob having a keeper adapted to register with theslot when the knob is applied to the spindle, a radially movable latchmounted in the spindle, an expandible sleeve insertible in the spindleand frictionally retained when inserted, and a dogging member on thesleeve engageable with the latch to project it through the slot in thespindle and into the keeper in the knob, and to retain the latch inprojected position.

3. In a structure of the character described, a tubular spindle having aslot formed therein, a knob having a keeper adapted to register with theslot when the knob is applied to the spindle, a radially movable latchmounted in the spindle, said latch having one end adapted to projectthrough the slot in the spindle and into the keeper in the knob, asleeve insertable in the spindle, a dog on said sleeve adapted to beinterposed between the inner surface of the spindle and the other end ofthe latch and thereby maintain the latch in projected position, andmeans for retaining the sleeve and the dog carried thereby againstaccidental release.

WALTER R. SCHLAGE.

